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PubMedDate not supplied

[Inheritance of frost resistance and winter hardiness in distant hybrids of wheat and amphiploids].

The data on inheritance of frost resistance and winter hardiness of bread wheat lines obtained as a result of distant hybridization of wheat-rye and wheat-elymus amphiploids with durum and bread wheat were presented. It was shown that selection of the donors of valuable traits is sensible to make in later progenies of hybrids (F6-F7). So, it is possible to obtain the new initial breeding material for winter bread wheat selection with high frost tolerance, winter hardiness and early maturity. Hypotheses explaining the high frost resistance of hybrids are presented. The crosses of the octoploid amphiploids with durum wheat are more preferable for the alien traits introgression into wheat than the crosses with bread wheat.

Adaptation, Physiological↗

PubMed2001

Clinal differentiation and putative hybridization in a contact zone of Pinus ponderosa and P. arizonica (Pinaceae).

The widely distributed Pinus subsection Ponderosae is a species complex that has a transition zone among taxa in the southwestern United States. In southern Arizona and New Mexico at least two recognized taxa, Pinus ponderosa var. scopulorum and Pinus arizonica or P. ponderosa var. arizonica, are known to coexist in close proximity. In this study, we report the existence of populations where the taxa are sympatric. One of the key characteristics distinguishing taxa is the number of needles per fascicle; P. ponderosa typically has three, P. arizonica has five. We examined the spatial distribution of needle-number types in a belt transect that covers a transition zone from nearly pure three-needle types at the top of Mount Lemmon to five-needle types downslope, in the Santa Catalina Mountains, Arizona. The spatial distribution is inconsistent with there being both free interbreeding among types and selective neutrality of types. Trees with intermediate types, having combinations of three, four, and five needles and/or mean numbers of needles between 3.0 and 5.0, are spatially concentrated in the middle of the transition zone. The spatial distribution supports the occurrence of hybridization and introgression, and this is consistent with reported crossabilities of the types. The results suggest that selection is acting, either on needle number per se or on other traits of the ecotype with which it may be in linkage disequilibrium, to maintain the observed steep clinal differentiation.

Journal Article↗

PubMed2001

Isolation of a chromosomally engineered durum wheat line carrying the Aegilops ventricosa pchl gene for resistance to eyespot.

The chromosome 7Dv of Aegilops ventricosa (syn. Triticum ventricosum, 2n = 4x = 28, genome DvDvMvMv) carries the gene Pch1 for resistance to eyespot. This gene has previously been transferred to chromosome 7D of bread wheat, T. aestivum (2n = 6x = 42, genome AABBDD). To (1) enhance the level of resistance of bread wheat by increasing the copy number of Pch1, and (2) create eyespot-resistant triticales, meiotically stable Pch1-carrying durum lines were selected from the backcross progenies of a cross between Ae. ventricosa and T. durum cv. Creso ph1c (2n = 4x = 28, genome AABB). The Pch1 transfer, likely resulting from homoeologous recombination, was located at the distal position on the long arm of chromosome 7A. The 7A microsatellite marker Xgwm 698 was found closely linked in repulsion to the introgression in the resistant recombination lines, and the endopeptidase allele located on chromosome 7A of cv. Creso ph1c was lost.

Chromosome Segregation↗

PubMed2001

Specific genetic markers for wheat, spelt, and four wild relatives: comparison of isozymes, RAPDs, and wheat microsatellites.

Three types of markers-isozymes, RAPDs (random amplified polymorphic DNAs), and wheat microsatellites- were tested on wheat, spelt, and four wild wheat relatives (Aegilops cylindrica, Elymus caninus, Hordeum marinum, and Agropyron junceum). The aim was to evaluate their capability to provide specific markers for differentiation of the cultivated and wild species. The markers were set up for subsequent detection of hybrids and introgression of wheat DNA into wild relatives. All markers allowed differentiation of the cultivated from the wild species. Wheat microsatellites were not amplified in all the wild relatives, whereas RAPDs and isozymes exhibited polymorphism for all species. The dendrograms obtained with RAPD and isozyme data separated Swiss wheat cultivars from those collected in Austria and England, while no difference was found between Swiss spelt and wheat. RAPD data provided a weak discrimination between English and Austrian E. caninus. The microsatellite-based dendrogram discriminated populations of Ae. cylindrica, but no clear separation of H. marinum from E. caninus was revealed. The similarity matrices based on the three different sets of data were strongly correlated. The highest value was recorded between the matrices based on RAPDs and isozymes (Mantel's test, r = 0.93). Correlations between the similarity matrix based on microsatellites and matrices based on RAPDs and isozymes were lower: 0.74 and 0.68, respectively. While microsatellites are very useful for comparisons of closely related accessions, they are less suitable for studies involving less-related taxa. Isozymes provide interesting markers for species differentiation, but their use seems less appropriate for studies of within-species genetic variation. RAPDs can produce a large set of markers, which can be used for the evaluation of both between- and within-species genetic variation, more rapidly and easily than isozymes and microsatellites.

Crosses, Genetic↗

PubMed2001

The genetic identity of alien chromosomes in potato breeding lines revealed by sequential GISH and FISH analyses using chromosome-specific cytogenetic DNA markers.

Genomic in situ hybridization (GISH) is one of the most popular and effective techniques for detecting alien chromatin introgressed into breeding lines; however, GISH analysis alone does not reveal the genetic identity of the alien chromosomes. We previously isolated a set of bacterial artificial chromosomes (BACs) specific to each of the 12 potato chromosomes. These BAC clones can be used as chromosome-specific cytogenetic DNA markers (CSCDMs) for potato chromosome identification. Here we demonstrate that GISH and fluorescence in situ hybridization (FISH), using CSCDMs, can be performed sequentially on the same chromosome preparations. Somatic metaphase chromosomes prepared using an enzymatic digestion and "flame-drying" procedure allows repeated probing up to five times without significant damage to chromosome morphology. The sequential GISH and FISH analyses reveal the genomic origin and genetic identity of the alien chromosomes in a single experiment and also determine whether an alien chromosome has been added to the genetic background of potato or is substituting for a homoeologous potato chromosome. The sequential GISH and FISH procedures should be widely applicable for germplasm characterization, especially in plant species with small-sized chromosomes.

Chromosomes↗

PubMed2001

Marker-assisted selection for identification of plant regeneration ability of seed-derived calli in rice (Oryza sativa L.).

Quantitative trait loci (QTL), associated with the ability of plant regeneration from seed-derived callus of rice, were mapped using a recombinant inbred (RI) population from Milyang 23/Gihobyeo. Each flanking marker, RZ474 and RZ575, tightly linked to two QTLs (qSGR-3-1 and qSGR-3-2) that are located on chromosome 3 was used in marker-assisted selection (MAS). These markers were tested on IR 36/MG RI036 (F3), Milyang 23/MG RI036 (F3), and forty-one rice cultivars. A restriction fragment length polymorphism (RFLP) marker, RZ575, that is located on chromosome 3 could effectively differentiate lines with high and poor regeneration ability, based on marker genotypes. This marker might be applicable for screening rice germplasms with high regeneration ability. Its introgression into elite lines might also be valuable in breeding programs to develop highly responsive genotypes to tissue culture.

Breeding↗

PubMedDate not supplied

[New morphological marker for chromosomes of the fourth homologous group of Triticinae].

The character "hairy leaf sheath" was studied in two groups of introgressive common wheat lines. The first group involves lines containing genetic material of Aegilops sharonensis, the second one includes lines with chromatin of Triticum miguschovae. The gene controlling hairy leaf sheath, Hs, was located by us on chromosomes 4S1 (Ae. sharonensis) and 4D (T. miguschovae) due to its joint transfer with beta-Amy-S(1)1, beta-Amy-D1, Acph-S(1)1 and Acph-D1 genes situated on the and 4D chromosomes. The possibility to use the identified gene as a morphological marker for these chromosomes was shown.

Chromosome Mapping↗

PubMed2001

Evidence that the Lore-1 region specifies ethanol-induced activation in addition to sedative/hypnotic sensitivity to ethanol.

BACKGROUND: Low-dose ethanol-induced activation (LDA) and initial sensitivity to alcohol are both predictors of alcohol abuse in human populations. Our hypothesis is that one or more genes specifying hypnotic sensitivity also specify LDA. We tested this hypothesis by using congenic mice derived from the inbred long-sleep (ILS) and inbred short-sleep (ISS) strains, which carry an ILS region introgressed onto an ISS background. METHODS: LDA was assessed by assigning mice randomly to receive one of five doses of ethanol ranging from 1.2 to 2.4 g/kg. On day 1, animals were injected with saline and placed in a brightly lit activity monitor for 30 min, after which they were returned to their home cages. On day 2, mice were injected with ethanol (20% w/v), their activity was monitored for a 30-min period, and LDA was determined by subtracting day 1 activity. The blood ethanol concentration of each animal was then assessed at 30 min by retro-orbital collection of 25 microl of blood. RESULTS: Ethanol had a significant effect on the activity of ISS mice, but ILS mice showed no activation at any dose, similar to the activities of the outbred lines. All three congenic strains were activated at several doses. Lore-2 and Lore-5 were not ILS-like (less active than ISS) at any dose. In contrast, ISS.ILS-Lore-1 congenics (carrying an ILS-derived Lore-1 allele on the ISS background) were significantly less activated than the ISS controls at 1.8 and 2.4 g/kg of ethanol. CONCLUSIONS: The Lore-2 and Lore-5 congenic regions do not affect LDA. In contrast, the Lore-1 congenic region carries one or more genes specifying both initial hypnotic sensitivity to ethanol and LDA.

Aging↗

PubMed2001

GISH technology in plant genome research.

Genomic in situ hybridization, a modification of fluorescence in situ hybridization technology, is one of the most exciting and versatile research tools to be developed in recent years. It has enabled plant chromosome and genome research to progress at phenomenal rate and its potential is far from exhausted. Genomic in situ hybridization has applications in characterization of genomes and chromosomes in hybrid polyploids, hybrid plants, partial allopolyploids, polyhaploids and recombinant breeding lines; and in the localization, and detection of amount of introgressed alien chromatin. Genomic in situ hybridization has also given new insights into somaclonal variation, the origin of B chromosomes, control of chromosome pairing and other aspects of chromosome evolution. This review highlights some of these areas and provides source material for the reader who seeks more information on a specific field.

Biological Evolution↗

PubMed2001

Identification of a major gene and RAPD markers for yellow seed coat colour in Brassica napus.

The development of yellow-seeded Brassica napus for improving the canola-meal quality characteristics of lower fibre content and higher protein content has been restricted because no yellow-seeded forms of B. napus exist, and their conventional development requires interspecific introgression of yellow seed coat colour genes from related species. A doubled-haploid (DH) population derived from the F1 generation of the cross 'Apollo' (black-seeded) x YN90-1016 (yellow-seeded) B. napus was analysed via bulked segregant analysis to identify molecular markers associated with the yellow-seed trait in B. napus for future implementation in marker-assisted breeding. A single major gene (pigment 1) flanked by eight RAPD markers was identified co-segregating with the yellow seed coat colour trait in the population. This gene explained over 72% of the phenotypic variation in seed coat colour. Further analysis of the yellow-seeded portion of this DH population revealed two additional genes favouring 'Apollo' alleles, explaining 11 and 8.5%, respectively, of the yellow seed coat colour variation. The data suggested that there is a dominant, epistatic interaction between the pigment I locus and the two additional genes. The potential of the markers to be implemented in plant breeding for the yellow-seed trait in B. napus is discussed.

Brassica napus↗

PubMed2001

Molecular characterization of a Thinopyrum intermedium group 2 chromosome (2Ai-2) conferring resistance to barley yellow dwarf virus.

The wheat--Thinopyrum intermedium addition lines Z1 and Z2 carry 21 pairs of wheat chromosomes and one pair of Th. intermedium chromosomes (2Ai-2) conferring resistance to barley yellow dwarf virus (BYDV). GISH results using the genomic DNA of Pseudoroegneria strigosa (S genome) as the probe indicated that the 2Ai-2 chromosome in Z1 and Z2 is an S-J intercalary translocation. Most of the 2Ai-2 chromosome belongs to the S genome, except for about one third in the middle region of the long arm that belongs to the J genome. The results of detailed RFLP analyses confirmed that the 2Ai-2 chromosome is extensively homoeologous to wheat group 2 chromosomes. Some new RFLP markers specific to the 2Ai-2 chromosome were identified. A RAPD marker, OP-R16(340), specific to the 2Ai-2 chromosome, was screened. We converted the RAPD marker into a sequence-characterized amplified region (SCAR) marker (designated SC-R16). The study establishes the basis for selecting translocation lines with small segments of the 2Ai-2 chromosome and localizing the BYDV resistance gene when introgressed into a wheat background.

Chimera↗

PubMed2001

Molecular phylogenetics relationship between six Chinese native pig breeds and three Swedish pig breeds from mitochondrial DNA.

Mitochondrial DNA genetic polymorphisms were used to evaluate the relationship between 6 Chinese indigenous pig breeds and 3 Swedish domestic pig breeds. A total of 440 bp of the control region and 798 bp of cytochrome b (cyt b) gene of mtDNA were determined from 140 pigs of 9 different breeds. The results of phylogenetics analysis showed that 6 Chinese native pig breeds originated from the Asian wild boar. The pairwise nucleotide sequences divergence suggested that they might occur about 413,000-875,000 years before present (YBP) between Chinese native pig breeds and European wild boar, and approximately 7,500-15,600 YBP between Chinese native pig breeds and Asian wild boar. Three Swedish pig breeds are present both European clade and Asian clade, which is due to the documented introgression of Chinese pig breeds into European domestic pig breeds 2 thousand years ago or during early 18th century.

Animals↗

PubMed2001

[Molecular tagging and mapping of QTLs for super quality fiber properties in upland cotton].

A G. anomalum introgression line, 7235, characterized as super quality fiber properties, was used to identify molecular markers linked to fiber property QTLs. By use of (7235 x TM-1)F2 in Nanjing and College Station, USA, and (7235 x TM-1)F3 in Nanjing and Hainan. Bulked segregation analysis was employed to produce 3 pairs of mixed DNA pools for fiber strength, micronaire and fiber length according to individual value of (7235 x TM-1)F2 and F2:3. A total of 221 pairs of SSR primers, 1,840 arbitrary 10-mer oligonucleotide primers and 77 ISSR primers were used to screen polymorphism between two parents, and 3 pairs of bulked DNA pools. Fifteen markers amplified by thirteen primers were identified to be linked with fiber quality QTLs through DNA polymorphism surveying between the parents, and then paired bulked DNAs, and screening the individual plant of (7235 x TM1)F2. Linkage test indicated 15 markers could be mapped to three linkage groups. In the first linkage group, eight markers (two SSR and six RAPD markers) associated with fiber strength were tightly linked with 2.2 cM interval genetic distance on average, and located on chromosome 10 in cotton. Two major QTLs for fiber quality characters were identified. One for fiber strength could explain 35% of the phenotypic variation in F2, and 53.8% in F2:3 at Hainan, which has the greatest single QTL effect of fiber strength and could be identified in all four environments, and tightly linked to 6 RAPD markers and 2 SSR markers with genetic distance no more than 16 cM in chromosome 10, in which FSRl933 is the nearest with the distance no more than 0.6 cM. One QTL linked to FMR1(603) for Micronaire could explain 7.8% of the phenotypic variation in F2, and 25.4% in F2:3 at Hainan, and expressed in all four environments. One QTL linked to FLR1(1550) for fiber length could explain 9.5% of the phenotypic variation in F2:3 at Hainan, very little in other environments. So they can be used in marker-assisted selection in increasing fiber quality of commercial cultivars.

Chromosome Mapping↗

PubMed2001

High gene flow levels lead to gamete wastage in a desert spider system.

Field censuses, breeding experiments, and a quantitative model are used to obtain insight into the extent and consequences of genetic mixing between locally adapted populations of a desert spider. Typically, 9% of the matings of desert riparian spiders (non-aggressive phenotype) in native habitat involve an arid-land partner (aggressive phenotype). Mating was found to be random with respect to behavioral phenotype, but linearly related to both the rate of immigration and survival of immigrants from surrounding arid habitats in the riparian area. Genetic mixing between riparian and arid-land spiders produces offspring that exhibit lower rates of survival in riparian habitat. Two extreme behavioral phenotypes were also observed in the field studies: approximately 5% of the female spiders attacked all males they encountered while another 22% ran from all potential mates. Punnett square analyses of the potential genotypes produced by introgression between arid- and riparian-adapted spiders indicate that these extreme phenotypes appear in F2 generation hybrids and backcrosses. Because there is a costly wastage of gametes in the case of mixed phenotype mating, model results indicate that within three generations of the cessation of gene flow, the riparian population would be free of mixed genotypes and moving towards genetic differentiation.

Alleles↗

PubMed2002

[Homoeologous grouping of R. kamoji chromosomes introduced in wheat using RFLP molecular marks].

Twenty six DNA probes from seven homoeologous groups of triticeae were screened to reveal the RFLP between 45 wheat-R. kamoji derivatives and their parents R. kamoji, Chinese Spring, Yangmai 5. The result showed that the introduced R. kamoji chromosomes in 16 wheat-R. kamoji alien chromosome lines including additions, substitution or putative translocations were grouped into homoeologous group 1, 3, 5, 6 and 7. Alien chromosome pairs could be readily transmitted into the descendants. The added chromosomes in K139, K141, K214, K218, K219 and K224 disomic addition lines were grouped into homoeologous group 1, but the added chromosomes in K214 and K218 were different from K219 and K224 which originated from different genomes of R. kamoji. Ditelosomic addition line K147 might involve a R. kamoji chromosome long arm homoeologous to group 1 of wheat, and the added R. kamoji 1 L chromosomes in K139, K141 and K147 probably derived from different three genomes of R. kamoji. U chromosome of R. kamoji. showed homology to wheat homoeologous group 1. Homoeologous group 1 chromosome of R. kamoji, particularly its long arm is related to genes for scab resistance. Result also demonstrated a possible rearrangement occurred between homoeologous group 1 and group 6 of R. kamoji. Two R. kamoji chromosomes introduced in K203 were grouped to homoeologous group 1 and 6, respectively. In K166, the introgressed R. kamoji chromosome involved the short arm of group 5. Another alien chromosome line K177 was revealed as to be with introduced chromosome involving group 5L, 6S and 7SL of R. kamoji. Results also confirmed the homoeology between S, H and Y genomes of R. kamoji.

Chimera↗

PubMed2002

[Phylogenetic relationship of mitochondrial DNA in salmonids of the subfamily Salmoninae: analysis of the cytochrome b gene sequences].

On the basis of comparison of the cytochrome b gene nucleotide sequences from genetic databases, the possible phylogenetic relationships of mitochondrial DNA (mtDNA) among all major lineages of Salmoninae (Brachymystax, Parahucho, Salvelinus, Salmo, Parasalmo, and Oncorhynchus) were examined. Three different phylogenetic methods (UPGMA, NJ, and ML) yielded phylogenetic trees of essentially the same topology: (((Brachymystax, Parahucho), Salvelinus, Salmo), (Parasalmo, Oncorhynchus)). The results obtained using the maximum parsimony method were less clear. Apparently, the divergence of the main salmonid lineages occurred during a relatively short time period; hence, the number of synapomorphs marking the order of their divergence was extremely low. This may account for the relative failure to use the maximum parsimony method of phylogenetic reconstruction. The problem of concordance of mtDNA and species phylogenetic schemes is discussed. Their discrepancy in salmonids may be caused by interspecific introgressive hybridization.

Animals↗

PubMed2001

Cytotaxonomic characteristics of the genus Glyptotendipes Kieffer (Chironomidae, Diptera) from fish and retention ponds (Silesia, southern Poland).

The cytotaxonomic characteristics of species of the genus Glyptotendipes (Chironomidae): G. glaucus Meigen, G. paripes Edwards, and G. barbipes (Staeger) are described. The studied material was collected from a fish pond at Gołysz and a sewage retention pond at Chybie in Silesia. All the studied species have the chromosome set 2n = 8, but with many specific structural and functional changes. The cytogenetic data of G. glaucus showed that the studied specimens of this species have been produced by the introgressive hybridization of two sibling species: G. glaucus x G. pallens, and subsequent crossing-over in the hybrid chromosome CD. Owing to this process, the band pattern of chromosome arm D coincided with those of G. pallens. New aberrations (homo- and heterozygous deletions in arm G as well as heterozygous inversions in chromosome arm B) were detected in G. glaucus. Specific band sequences were discovered in chromosomes of G. paripes. The band patterns established in chromosomes AB and G of this species were identical with those of Siberian populations. The banding patterns of the polytene chromosomes of G. barbipes do not differ from the standard. However, high frequency of pericentric inversion of chromosome AB was established. Many new puffs were found in the polytene chromosomes of all the studied species. Their nucleolar organizer was very sensitive to environmental changes. In G. glaucus it appeared in three different states: very active, slightly active, and heterozygous state. The organic pollution existing in the sewage retention pond may contribute to possible mutations and chromosomal damage in Glypotendipes species. Structural and functional rearrangements of the polytene chromosomes of these species mobilized their genomes and provide for survival under polluted conditions.

Adaptation, Physiological↗

PubMedDate not supplied

[Comparative analysis of the genetic structure of hybrid populations of European toads of the genus Bombina (Oken, 1816) from Ukraine and Croatia].

The comparative analysis of hybrid populations of toads Bombina bombina and B. variegata from Ukraine and Croatia revealed the essential differences in their genetic structure. The population composition and the direction of genetic introgression are determined initially by the ecological factors (the locality type, the country relief). The clear predominance of the red-bellied toad Bombina bombina was found in two cases: in the lowland populations and in the big samples. The second parental species, B. variegata, predominates in the highlands and in the small samples, respectively.

Alleles↗